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to state accurately users’ requirements for a new information processing system.

Event analysis treats the system as a...

black box and views it from a stimulus-response perspective.

An event is

an occurrence which takes place at a specific time and triggers a predetermined response from the system. Because events occur independently of each other, event analysis is a powerful technique for breaking up a large or complex system into small, manageable, cohesive, independent parts.

Event analysis...

identifies the events to which the system is expected to respond, names the inputs and outputs, and identifies the actors – those who interact with the system by providing inputs and receiving outputs.

The Primary Goal of Systems Analysis is

To state accurately the users’ requirements for a new information processing system

Secondary Goals of System Analysis are

To understand the users’ requirements.
To communicate the current understanding of the proposed system
To prevent expensive mistakes
To state a design problem
To state the conditions for system acceptance

5 Characteristics of a Statement of System Requirements

Graphic: Uses diagrams
Partitioned: Organizes the system description into comprehensible parts
Non-redundant: A change can be made in a single place
Accurate: Rigorous, precise, clear, consistent, and complete
Minimal: Eliminates non-essentials, while including all critical details

6 Step Procedure for Object-Oriented Systems Analysis

Step 1. Identify the business events and make an event table.
Step 2. Identify the use cases and produce a use case diagram for the system.
Step 3. Write a use case narrative describing the system’s response to each business event.
Step 4. Draw a system sequence diagram for each use case scenario.
Step 5. Produce a domain model showing the concepts, attributes, and associations in the problem domain of the system.
Step 6. Write a contract for each system operation.

Event-Driven Systems

Event analysis takes a stimulus-response perspective

The system does nothing until it is triggered by an event.
When an event occurs, the system responds as completely as possible.
After the response is complete, the system waits until another event occurs.

An event is

an occurrence which takes place at a specific time and initiates or triggers a predetermined response from the system.

An external event is

an event which occurs outside the system boundary.

An internal event is

an event which occurs inside the system boundary.

A temporal event is

an event which occurs at a prespecified time.

Event analysis creates a system description by identifying:

The events to which the system is expected to respond
The incoming message (event flow or
data flow) associated with each event
The desired response
The actions or behaviors required to generate the response for each stimulus

Hints About Event Analysis

Ignore the technology of implementation – build an essential event model.
Model the system’s complete
response – don’t split a single event into fragments.
Isolate individual events – don’t combine events if the system must wait in between them.

The initial step in object-oriented systems analysis is

event analysis.

Event analysis identifies ..

external and temporal events and the system’s expected responses.

Models for Object-Oriented Systems Analysis

Models for Object-Oriented Systems Analysis

Typical Models – Event List

Typical Models – Event List
Event list for the university registration system